DEVELOPMENT AND VALIDATION OF INDIRECT SPECTROPHOTOMETRIC METHODS FOR LAMOTRIGINE IN PURE AND THE TABLET DOSAGE FORMS

Three simple, sensitive, accurate and indirect visible spectrophotometric methods have been developed for the estimation of lamotrigine (LMT) in both pure and in pharmaceutical preparations. They are based on the oxidation of lamotrigine with a known excess of cerium(IV) in acid medium. The unreacted cerium(IV) oxidize leuco crystal violet to crystal violet colored dye (Method A), leuco malachite green to bluish-green malachite green dye (Method B), leuco xylene cyanol FF to xylene cyanol FF bluish dye (Method C) and exhibiting absorption maxima (λmax) at 580, 610 and 610 nm, respectively. In these methods, the amount of cerium(IV) reacted corresponds to the amount of LMT. The results of the three methods have been validated statistically and by recovery studies. The results obtained in the proposed methods were in good agreement with the label claim.